Rockerarm assembly for internal combustion motors



1961 L. LOMBARDI ,970,585

ROCKERARM ASSEMBLY FOR INTERNAL COMBUSTION MOTORS Filed Dec. 7, 1959 FIG.

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A 7' TORNE' Y United States Pater 1th).

The present invention relates to a rockerarm assembly for an internal combustion motor, and has for an object a construction which increases the efiieiency and power output of the motor.

Tests which I have made clearly indicate that an internal combustion engine which utilizes rockerarms actuated by push rods through tappets and earns to open poppet. valves, requires an expenditure of power for their operation. This particularly true for high speed motors such as used in racing cars. As a rule, the push rods and tappets all hang from one end of the roekerarms thus imposing weight thereon and this excess weight must be lifted by the cams on the camshaft. The present invention overcomes the weight problem of the push rods and tappets in a novel and eificient manner and in a manner which permits easy assemblage of my invention in most internal combustion motors.

With the above and other objects in view, the invention consists in the novel and useful provision, formation, contruction, association and relative arrangements of parts, members and features, all as shown in one embodiment in the accompanying drawing, described generally, and more particularly pointed out in the claims.

In the drawing.

Figure 1 is a vertical section of the rockerarm assembly of the invention;

Figure 2 is a fragmentary, sectionalview on the line 22 of Figure 1, and on enlarged scale;

Figure 3 is a fragmentary, sectional view on the line 33 of Figure 1, and on an enlarged scale;

Figure 4 is a fragmentary, top plan view of the rockerarm and rockerarm shaft shown in Figure 1; and,

Figure 5 is a sectional view on the line 55 of Figure 1, and on an enlarged scale.

Referring to the drawing, I have illustrated in Figure 1 the rockerarm assembly of the present invention, and wherein a portion of the motor block is shown at 1, and which block is constructed to have a port 2, a valve seat 3, for the head 4 of a poppet type valve, the valve having a stem 5 passed through a bore 6 in the block 1 and through a guide extension 7. The stem 5 carries a spring retainer cup 8 and included between the retainer cup and the block and surrounding the extension 7 is a coil spring 9 which urges the head 4 to its seat 3. I provide a rockerarm 10 loosely mounted on the usual rockerarm shaft 11, one end of said rockerarm being provided with a transverse threaded bore 12 for passage therethrough of a threaded rod 13, with one end of the rod adapted to contact with an end of the valve stem 5, as shown at 14. The rod 13 is locked to the rockerarm by the means shown at 15 which includes a threaded boss 16 formed on said rockerarm. The rod 13 is secured against turning movement by two lock nuts 17 and 18. The rod 13 may be rotated by a screw driver engaging kerf 19 to adjust the distance of projection thereof for contact with the top of the valve stem 5 to adjust for valve opening. Thus after having made the adjustment for rod 13 relapatented Feb. 7,1951

tive to the end of the valve stem, the nuts 17 and 18 may be tightened against the boss 16.

The rockerarm 10 is so constructed that arm 20 thereof has greater weight than the arm 21. The width and'depth of arm 20 will depend upon the material used for the rockerarm construction, and likewise the weight of the tappet, push rod, and associated members interconnect ing the push rod with the arm 21 and with a tappet. The arm 20 should have a weight suflicient to counterbalance the weight of the push rod, tappet and assoicated elements. The push rod'22, in the present instance, is shown as tubular and one end thereof is secured to the arm 21 in the manner shown in Figure wherein the push rod is internally screw threaded at 23 to receive a threaded shank 24 to which a ball 25 is secured. The arm 21 is provided with a screw threadedbore 26 and a hemispherical socket or seat 27. A nut 28 is externally threaded for --connection with the screw threads 26 and the nut is provided with a hemispherical socket 29. Ball 25 is adapted for reception in the sockets 27 and 29- when the nut 28 engages threads 26'. The nut 28is provided with an outwardly divergent conical or tapper ed bore 30 which communicates with socket 29. The tapered bore permits the push rod to swing laterally. After adjustment of nut 28 relative to rockerarm 21 so that the ball 25 may move in the sockets 27 and 29, lock nuts 31 and 32 are tightened on the threads of nut 28 against arm 21.

The construction described for one end of the push rod 22, to wit, the ball secured to the push rod by the screw threaded shank, together with the lock nuts, is the same for the opposite end of said push rod and accordingly, the same numerals will be applied in Figure 3, as applied in Figure 2. In Figure 3, however, a tappet 33 is provided with a screw threaded bore 34, for receiving the nut 28 and an end of the tappet within the screw threaded bore is formed with a hemispherical socket 35 for receiving the ball 25. As illustrated best in Figures 1 and 5, the upper end of the tappet is angle sided and is shown as hexagonal at 36. In accordance with usual practice, the tappet is movable within a guide bushing 37 and a cam 38 mounted on a suitable cam shaft engages the base of the tappet to raise and lower the same as the camshaft is rotated.

The operation, uses and advantages of the invention just descirbed, are as follows.

vI assume that there will be both intake and exhaust valves for each motor cylinder, each one being arranged as shown in the drawing and provided with rockerarms of the constructiton described. Each rockerarm will be so constructed and weighed that the arm portion 20 will counterbalance the Weight of the arm 21 and parts associated therewith, to wit: the push rod 22 and balls 25 with fittings, tappet 33 with associated fiittings which include the nuts 28 and lock nuts 21 and 32. This counterbalancing also includes the rod 13 adjustably carried by the arm 20 so that the arm 20 plus the rod 13 and associated parts will counterbalance the arm 21 with its associated parts. The result is that cam 38 in its rotation only compresses the spring 9 to move the valve head and its stem from the seated position shown and allow return of the valve head to its seat. Thus the rockerarm assembly becomes more sensitive, acts faster, and weight load is reduced. For convenience in the claims, the push rod 22 and tappet 33 together with the ball and socket connections between the push rod and arm 21 of the rockerarm as well as the ball and socket connection between the push rod and tappet 33, I have designated as the push rod tappet assembly, while the opposite end of said rockerarm which moves the stem 5, compresses the spring 9, and opens the valve 4 from its seat 3, I designate as the valve assembly. It is realized that the push rod 22, tappet v 33 and the ball and socket members secure the push rod from. The opposite end 20 f said rockerarm moves the stem 5 downwardly to open the valve from its seat under closing pressure of spring 9 with said end 20 of the rockerarm not supporting any weight. Thus it is thatthe arm 20 must be of greater weight than the arm 21 to counterbalance the push rod tappet assembly.

I claim:

: -l. A rockerarm assembly for internal combustion motors, the internal combustion motor being of the type which includes a camshaft, a tappet to be moved by the camshaft and a push rod together with a valve assembly, the valve of which is to be opened and closed to a valve seat; said rockerarm being mounted on a shaft, a ball and socket connection between one end of said rockerarm and one end of the push rod and a ball and socket connection for the opposite end of the push rod and the tappet, the opposite end of the rockerarm being weighted to counterbalance the weight of the push rod, tappet and ball and socket connections.

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and tappet assembly to the arm 21 and" are pendent there said nut provided with a hemispherical socket facing the socket of the rockerarm, said not provided with a tapered bore communicating with the hemispherical socket thereof, a threaded shank and a ball secured to said shank at one end thereof, said ball adapted for placement between the hemispherical sockets of the rockerarm and of the nut, a push rod having threaded engagement with the threaded shank for the ball, a valve tappet within a guide sleeve, said tappet formed with a threaded bore and with a hemispherical socket, a nut formed with a hemispherical socket and with a conical bore communicating with the hemispherical socket, a screw threaded shank provided at one end with a ball, the ball adapted to be seated within the sockets of the tappet and of the nut, and said threaded shank of the second named ballbeing secured to the push rod, and the rockerarm provided with a counterweight for counterbalancing the opposite arm of the rockerarm including the weight of the push rod, balls connected to the push rod nuts and tappet.

References Cited in the file of this patent UNITED STATES PATENTS Miller et al Mar. 26, 1929 1,948,288 Corey Feb. 20, 1934 2,877,652 Muschalek Mar. 17, 1959 

